The present invention relates to a device for administering a wound sealant and more particularly to a fan-shaped pre-loaded cannula attached to a syringe device for administering a wound sealant directly to an incision site on the eye.
Anatomically, the eye is divided into two distinct parts—the anterior segment and the posterior segment. The anterior segment extends from the outermost layer of the cornea (the corneal epithelium) to the posterior of the lens capsule. The posterior segment includes the portion of the eye behind the lens capsule. The posterior segment extends from the anterior hyaloid face to the retina, with which the posterior hyaloid face of the vitreous body is in direct contact. Ocular surgery involves making an incision to gain entry to the eye. Various surgical procedures are commonly performed on the anterior and posterior segments of the eye. In the anterior segment, cataract surgery is most common. In the posterior segment, a number of vitreo-retinal procedures are most common.
The eye's natural lens is composed of an outer lens capsule enclosing a lens cortex. Since the human eye functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a clear crystalline lens onto a retina, the quality of the focused image depends on many factors including the transparency of the lens. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is cataract surgery which involves the removal and replacement of the lens cortex by an artificial intraocular lens (IOL).
In the United States, the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, an incision of a few millimeters in size is made in the cornea or sclera. By way of the incision, a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. The vibrating cutting tip liquefies or emulsifies the lens cortex material so that it may be aspirated out of the eye. The diseased lens material, once removed, is replaced by an IOL.
The IOL is injected into the eye through the same small incision used to remove the diseased lens cellular material. The IOL is placed in an IOL injector in a folded state to avoid enlarging the incision. The tip of the IOL injector is inserted into the incision, and the lens is delivered into the lens capsular bag.
Vitreo-retinal procedures include a variety of surgical procedures performed on the posterior segment of the eye to restore, preserve, and enhance vision. A vitrectomy is a common part of a vitreo-retinal procedure. A vitrectomy, or surgical removal of the vitreous body, may be performed to clear blood and debris from the eye, to remove scar tissue, or to alleviate traction on the retina. The vitreous body is also removed if it is pulling or tugging the retina from its normal position. Some of the most common eye conditions that require a vitrectomy include complications from diabetic retinopathy such as retinal detachment or bleeding, macular hole, retinal detachment, pre-retinal membrane fibrosis, bleeding inside the eye (vitreous hemorrhage), injury or infection, and certain problems related to previous eye surgery.
A surgeon performs a vitrectomy with a microscope and special lenses designed to provide a clear image of the posterior segment. Several tiny incisions are made on the sclera at the pars plana. The surgeon inserts microsurgical instruments through the incisions, such as a fiber optic light source to illuminate inside the eye, an infusion line to maintain the eye's shape during surgery, and instruments to cut and remove the vitreous body.
During each of these ophthalmic procedures, one or more tiny incisions are made to gain access to the various eye structures. These incisions are typically made with custom knives that produce a specific wound geometry. The wound geometry allows access for various surgical instruments. At the conclusion of the procedure, it may be necessary to close the incisions. Because the eye is very sensitive to traditional forms of wound closure, like sutures, various wound sealant compounds may be advantageously used. Some sealants are applied as one part and others are composed of two or more parts that must mix simultaneously to form a seal. For ocular incisions, the quantities of sealant required can be very small, on the order of a few microliters. Formation of a strong seal can require complete coverage of the incision in a single application. Applying these compounds can be difficult because of the location and geometry of the wound, and because of the anatomy of the eye.
For example, a blade may be coated with a sealant and placed inside an incision. However, this process requires proper placement of the sealant on the blade and care in its application. With a blade smaller than the incision, a stroking motion (in-and-out and/or side-to-side) would be required to coat the entire surface of the incision. The brief presence of the blade in between the inner surfaces of the incision can hinder the formation of a strong adhesive seal with complete coverage. Distortion of the incision by insertion of a blade or simple cannula can cause gaping and leakage of intraocular fluids which interferes with strong seal formation.
Effective sealant use in the eye requires a different device and method than for other applications. Accordingly, it would be desirable to have a specially designed fan-shaped pre-loaded cannula attached to a syringe device for injecting small quantities of wound sealant simultaneously and with complete coverage to the entire incision site on the eye with minimal gaping.